EM 1110-2-1100 (Part V)
31 Jul 2003
- The NPS strategy was to use the Cape Hatteras Lighthouse relocations as an example and model
of "enlightenment" (page numbers refer to NRC 1988)
-
"an exemplary response ... to the generic problem of shoreline erosion" (p. 72)
"attract much media attention ... to educate a large national audience on the nature of
coastal barriers" (p. 72)
"use national parks as models of wise management of natural and cultural resources"
(p. 71)
"act as a signal to the country of the problems confronting the coast" (p. 39) and
"illuminate approaches to solving the problems of living with a rising sea" (p. 39).
The Cape Hatteras Lighthouse was moved successfully inland about 488 m (1,600 ft) from the mhw
shoreline in 1999. Recognizing the engineering and construction skills required to complete the
move safely, the project received the Outstanding Civil Engineering Achievement Award from the
American Society of Civil Engineers in 2000.
In the final analysis, the NPS policy against any structural interference with natural, coastal processes
was the deciding factor. The decision to relocate was taken in 1989 at a time when the possible,
accelerated rise in sea level was also of major concern.
(4) Impact of sea level rise. A detailed summary of present-day knowledge of sea level rise rates is
presented in Part IV-1-6. Substantial variability exists when including local subsidence as previously
discussed for Baytown, Texas. A National Academy of Sciences report on engineering implications (National
Research Council 1987) concluded that whether to defend or to retreat depended on several factors, but
mainly the future sea level rise rate and the cost of retreat which varies by site. The NRC recommended that
all options should be kept open to enable the most appropriate response to be selected. Retreat is most
appropriate in areas of low development. Given that a proper choice exists for each location, selecting an
incorrect response alternative could be unduly expensive (National Research Council 1987).
V-3-5. Combinations and New Technologies
Pope (1997) lists the following common types of coastal erosion and flooding problems:
Long-term, chronic land loss associated with the erosion of cohesive sediments, reduced supply of
sandy sediments, and/or subsidence.
Localized erosion impacts caused by a navigation project jetties or other coastal construction works.
Lands and facilities impacted by storm-induced erosion.
Flooding by a storm surge with associated wave attack damages.
Loss of environmental resources (i.e., wetlands, oyster reefs, nesting areas, etc.).
Need for more land.
In many cases, combinations of these problems exist that require a combination of structural measures
together with nonstructural alternatives to be implemented within a comprehensive, coastal region,
management plan for hazard reduction.
V-3-86
Shore Protection Projects
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